Sleep Cycle Calculator

Calculator Tools

Best bedtime based on 90-minute cycles

FreePrivateInstant
I want to wake up at
Minutes to fall asleep
Full guide, 3 min readSleep in 90-minute cycles: when to go to bed so the alarm does not feel like an attackRead the story behind this tool →
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History

All history →

Sleep Cycle Calculator — at a glance

Wake up fresher by timing your sleep in 90-minute cycles.

Input
Wake at 6:30 AM
Run
Result
Sleep at 9:15 PM (6 cycles)

How to use it — step by step

The time you want to wake up and how long you usually take to fall asleep.

1

Enter your values

Fill in the boxes. Sensible example values are already filled in for you.

2

Find Bedtimes

Press the button. The answer is worked out instantly on your device.

3

Read or copy the result

See the big answer and the extra details, then press Copy to keep them.

Pro tips

Small things that make the result better.

✦Aim for 5–6 cycles (7.5–9 hours) on most nights.
✦Keep the same wake-up time every day, even on weekends.
✦Avoid screens for 30 minutes before the bedtime shown.

Quick facts

90 minper sleep cycle
4 options3 to 6 cycles
Fall asleeptime included
Freeno signup

Frequently Asked Questions

Is a 90-minute cycle exact?+

It is an average. Real cycles vary between about 80 and 110 minutes from person to person.

Is this medical advice?+

No. If you have long-term sleep problems, speak with a doctor.

Is my data safe?+

Yes. Everything runs inside your own browser. Your text, files and images are never uploaded to any server.

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